In modern cataract surgeries, artificial lenses, so-called intraocular lenses, are standardly used in the capsular bag of the eye.
During the operation, an ocular incision of typically 2 to 4 mm is made, through which the natural lens is first removed and the implant is then inserted. For insertion, the artificial lens is introduced in a folded state through the incision in the capsular bag. Once the folded lens is inserted into the capsular bag, it unfolds back to its original shape
The artificial lenses which are presently common comprise an optical lens body and two or more peripherally extending haptics which are transverse to the optical axis of the lens body, said haptics serving as position springs for the lens body within the capsular bag. For example, two haptics, which are arranged opposite one another on the lens body, extend in the same helical manner from the lens body.
Improved surgical tools and implants enable the surgeon to make visibly smaller incisions. The removal of the natural lens can presently be carried out through an incision of less than 2 mm. However, this only makes sense if the intraocular lens can be inserted through a similarly small incision.
For the insertion of intraocular lenses have been developed in recent years lens carriers or cartridges, in which a lens can be loaded and then ejected from the lens carrier by means of an injector.
Examples of such lens carriers or cartridges and injectors are known, for example, from patents U.S. Pat. Nos. 6,267,768, 5,810,833, 6,283,975, 6,248,111, 4,681,102, 5,582,614, 5,499,987, 5,947,975, 6,355,046 and EP 1 290 990 B1, as well as the disclosures US 2004/0199174 A1, EP 1 905 386 A1 and WO 03/045285 A1.
In the injector device according to U.S. Pat. No. 4,681,102, the cartridge which is formed as the folding device for the lens and the injector nozzle are separate parts. The cartridge can be inserted into the injector, whereupon the injector nozzle can be screwed onto the front of the injector housing.
In the injector device according to U.S. Pat. No. 5,582,614 and most known injector devices, such as U.S. Pat. Nos. 6,267,768, 5,810,833, 6,283,975 and U.S. Pat. No. 6,248,111, the cartridge is integrally formed from a folding device and an injector nozzle.
Intraocular lenses are sterile packed by the manufacturer and, if appropriate, come in a liquid bath. Depending on the lens material, storage in a liquid may be necessary to protect the lens from drying out. During surgery, the lens must be removed from the packaging in a sterile field and inserted or loaded into a cartridge or directly into an injector. Because these lenses represent very small and elastic structures, the risk exists when loading the cartridge or the injector that the lens is dropped or springs away during folding, thus losing its sterility. In addition, the lenses are very delicate structures which can easily be damaged during folding, injecting and reloading in a cartridge. The risk of damage is especially large for the so-called haptic which surrounds the optical portion of the lens. It is also possible that the optical part is damaged, for example by the forceps during insertion into the cartridge. These risks are particularly large in the cartridge according to U.S. Pat. No. 4,681,102, which provides no measures for detecting the lens edges during folding. In contrast, U.S. Pat. No. 5,582,614 proposes the introduction of grooves in the free ends of the half-shells of the cartridge, said grooves detecting the lens edges during folding of the lens. U.S. Pat. No. 5,499,987 provides grooves in a specific embodiment. Specifically, it is proposed that the groove be formed less deeply toward the nozzle, so as to facilitate transport into the nozzle (FIGS. 34, 39, 40 and 41 in U.S. Pat. No. 5,499,987). It is, however, disadvantageous that cartridges with such grooves cannot securely grasp the lens edges if the lens has a relatively large diameter and the cartridge for the insertion of the lens must be opened widely, i.e. a large opening angle exists. This disadvantage is not present in the cartridge according to U.S. Pat. No. 5,947,975 or U.S. Pat. No. 6,355,046, as it possesses two hinges, so that a different folding geometry arises than that of cartridges with a single hinge. It is, however, disadvantageous that for each lens size, a cartridge corresponding to this sized is needed. A further disadvantage is that the folding of the lens is not optimal (FIG. 11 and FIG. 15 in U.S. Pat. No. 5,947,975 or U.S. Pat. No. 6,355,046), so that the diameter of the injector tip must be kept relatively large. For this reason, an undesirably large ocular incision is also necessary to insert the lens into the capsular bag of the eye.
As shown in EP 1 290 990 B1, WO 03/045285 A1 and EP 1 905 386 A1, this cartridge construction continued to be maintained in later years, said cartridge construction comprising two half-shells connected by a single hinge, whether with or without grooves or holding devices for grasping the lens edges.
The disclosure of WO 03/045285 A1, for example, shows a method for inserting an intraocular lens in the capsular bag of the eye in which an overpressure is generated in order to eject a loaded lens floating in a lubricant from the injector nozzle. a compressible and deformable piston continuously adapts itself to the forward-tapering nozzle channel. Along the way the lens is further folded and at the end of its journey has a very small diameter. Due to the deformability of the piston, the end of the nozzle channel may be kept very narrow, hence only a very small incision is necessary. A kit for carrying out the method contains a lens carrier and a lens. The lens is located on the lens carrier in a tensionless state. The lens and lens carrier may be supported by a holder and sterile packed in a package until use, and in the case of a hydrophilic lens, specifically in a liquid which protects the lens from drying out. During the operation, the lens carrier along with the lens supported therein are removed from the packaging, inserted into the injector and folded. A lubricating liquid is filled thereupon through the channel. The lens can then be injected into the capsular bag of the eye to be treated.
Because cartridges with ridges for grasping the lens edges are unsatisfactory during folding, a cartridge is proposed in US 2004/0199174 which likewise comprises two half-shells in the conventional manner. Therein is shown in particular an injector device in which the injector housing consists of a cylinder for receiving the piston, a folding device for the lens and an injector nozzle. In addition is provided a flexible elastic band, which leads from the first half-shell to the second half-shell and which can be pulled through a slot on the edge thereof. An intraocular lens is inserted between a loop of the band, and the half-shells. By pulling on the band, the half-shells can be moved toward each other, and the lens (which extends unfolded beyond the edges of the half-shells) is pressed into the half-shells, so that the intraocular lens is thereby folded. During folding, the lens is thus held by the band. The band acts as a folding aid. Disadvantageous is the complicated design of the cartridge and the complicated handling thereof. In addition, the haptics can be pinched, for example, between the band and the slot.
There are preloaded systems. These have already been loaded at the factory with a lens in the unfolded state (so-called preloaded systems), so that the previous delicate loading operation is no longer necessary before the operation. The surgeon need only undertake the folding process and introduce the lubricating liquid. Holders are known for preloaded systems which hold a preloaded lens during transport into its storage position. These holders are removed or fall off during folding of the lens, before the lens can be injected into an eye. The removal of a holder constitutes an additional manipulation step. A part which falls off may have a disruptive effect; for example, it must be collected and removed from the surgical area.
In general, systems for prefolded lenses and systems for lenses which are not prefolded can be distinguished in the prior art. In the systems without prefolded lenses, the lenses are folded only during the process of insertion for the injection. In particular, systems are used for this purpose in which the lens is loaded from the back into a loading chamber in a still unformed or unfolded state (as is shown for example in U.S. Pat. No. 5,810,833). Systems for lenses which are not prefolded disadvantageously require relatively large incisions, because during the process of insertion, a folding which is as small as desirable cannot occur for various reasons. In the systems with prefolded lenses, the lenses are folded or prefolded before the process of insertion for the injection. Winged cartridges are used in particular for this purpose (such as disclosed in U.S. Pat. Nos. 6,267,768, 6,248,111, 5,947,975 or U.S. Pat. No. 4,681,102). The lens is folded during closing of the winged cartridge and is present in a prefolded state in the loading chamber. Systems with winged cartridges advantageously require only small incisions. It is disadvantageous that the lens, in particular the haptic, can be pinched during insertion or folding, or the haptic can assume an unfavorable position during this process.
None of the previously mentioned documents disclose a system which can always be manipulated without failure and/or in which the risk that the haptic of the lens is pinched during folding is completely eliminated. A pinched or disadvantageously trapped haptic may break, at the latest, during injection of the lens. If many manipulation steps are necessary to prepare the lens and injector, this can represent a corresponding number of sources for error.
Advantages
It is therefore an advantage of the present invention to provide a device for easily loading an intraocular lens, which avoids the disadvantages of the described known systems and methods. In addition, a device is to be provided which folds an intraocular lens without damage during folding and/or injection and which is suitable for use with small incisions. In addition, an apparatus is to be provided which is optimized with regard to the manipulation steps for preparation of the lens and injector. In particular, as few manipulation steps as possible should be necessary which must be carried out on the device after delivery of the lens and injector and directly before the surgical procedure. Sources of error are thereby to be reduced. A further advantage is to provide a device which requires only small incisions in the eye during use.
These and other advantages are achieved by the features of the independent claims. Further developments and/or advantageous embodiments of the invention are subjects of the dependent claims.